GB2580018A

GB2580018A - Non-destructive testing tool for dual axis position encoding of an inspection probe

Info

Publication number: GB2580018A
Application number: GB1818337.6A
Authority: GB
Inventors: Ireland James
Original assignee: Advanced Mech Systems Ltd
Current assignee: Advanced Mech Systems Ltd
Priority date: 2018-11-10
Filing date: 2018-11-10
Publication date: 2020-07-15
Also published as: GB201818337D0

Abstract

A scanning tool for non-destructive testing comprising a probe clamping mechanism 100 with first and second omnidirectional wheels 103 extending in perpendicular directions from the probe clamping mechanism 100 and each including a wheel position encoding mechanism 102. The encoders 102 run along the X or Y scanning axis of the probe and the encoder may read the rotational position of the wheels 103 which can be magnetic. A loading component may press the wheels against a material surface and the device may use ultrasonic or eddy current flaw detection systems. The encoding mechanism 102 may have an adjustable fixing position so that the centre of the aligns with the centre of the probe.

Description

DESCRIPTION

NON-DESTRUCTIVE TESTING TOOL FOR DUAL AXIS POSITION ENCODING OF AN INSPECTION PROBE

BACKGROUND

[0001] The present invention relates to a tool used in the field of non-destructive testing for two-dimensional scanning of engineering materials with flat, curved or complex surfaces. The tool provides dual axis encoding functionality to a wide range of inspection probe types and sizes. Non-destructive testing is the process of evaluating materials, components or assemblies for flaws without destroying the product or material. The present invention is typically used for ultrasonic testing but can be used with several other non-destructive testing methods including eddy current. A typical ultrasonic testing system consists of a probe which is connected to a flaw detector. The device electronics within the flaw detector send a high voltage pulse to the probe which generates ultrasonic energy that propagates through the material in the form of waves. If there is a flaw in the material such as a crack, some of the waves will be reflected. The reflected ultrasonic waves are transformed into an electrical signal by the probe. The signal is processed by the flaw detector to be displayed as data on the screen. To scan the operator manually slides the probe over the material surface to produce a two-dimensional map of the flaw detection data. The encoder sends positional data to the flaw detector so the position can be tracked relative to a fixed reference point on the inspection material. As the probe scans along the surface the position data is referenced with the corresponding flaw data to be graphically represented on the screen.

[0002] Testing of parts such as pressure vessels or piping using manually operated dual axis probe scanning devices typically involve a scanning arm, frame or draw string mechanism which encode the two-dimensional position of the probe relative to a stationary material. These solutions are limited in terms of surface coverage size by the length of the arms frame or string and can accommodate only a small variation in curvature. For all but relatively flat geometry's positional accuracy may be lost as the geometry position assumes the surface is flat and variations in rise or fall are not accounted for. For geometry's with relatively small diameters such as pipes, coverage may not be possible as there is insufficient range of movement.

[0003] A simple and effective solution typically used to encode a manually manipulated probe along a single axis is to mount a wheel encoder to the probe via a spring-loaded bracket. To perform a scan the probe is manually swept along the axis whilst maintaining parallel orientation in the X or le axis. The wheel is pushed against the scanning surface by the spring loading mechanism to maintain constant contact to accurately and reliably translate the position data to the flaw detector. This solution is limited to a single axis because simply mounting a second wheel encoder with a perpendicular offset would cause a wheel to drag and cause friction as it is moved against the rotation axis resulting in inaccurate position data. The present invention utilises omnidirectional wheels to allow two perpendicularly offset wheels to simultaneously rotate in a way that can be translated by the X and 1' axis encoders with good positional accuracy. Omnidirectional wheels have small rollers around the circumference which are perpendicular to the direction the wheel rolls in. The wheel functions normally as it turns but if pushed in a direction perpendicular from the roll direction the rollers allow it to slide freely.

SUMMARY

[0004] Per the aspects illustrated herein, the present disclosure comprises of a probe clamp as well as X and Y axis position encoding components which interface with ultrasound or eddy current flaw detector equipment. The probe clamp serves to fix the tool to the probe and provide mounting points for the X and V encoding components. The clamp adjustment is made by rotating an adjusting screw to compress the gripping surfaces onto opposite sides of the probe and cause sufficient friction to securely fix it in place. The X and Y axis encoding components and are attached to the probe clamp via slotted rail fixings. The adjustable mounting feature of the encoding components is required to provide central alignment with the probe so a range of probe sizes may be accommodated. Both the X and Y axis encoding components are identical and include a rotary encoder, omni-directional wheel, spring-loaded mechanism and fixing plate. On one end of the base rail there is a fixed clamping arm which features a slotted fixing rail on one side and a soft gripping surface on the other.

[0005] The present invention is hand operated by pressing down on the top of the probe to apply surface loading whilst moving in the in the chosen scan pattern. During the scan the probe orientation is maintained parallel in the X or Y axis relative to the material. To act as a position, reference an X and Y axis grid pattern can be drawn onto the material surface. During the scanning operation, the spring-loaded bracket functions to load the omnidirectional wheel against the material surface.

As the probe is moved over the surface the omnidirectional wheel axis position is sensed by the encoder. The omnidirectional wheels allow for the wheel moving in the direction perpendicular to its axis to slide over the surface without rotating. The above defined and other features are illustrated by the following figures and detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] A scanning tool according to the invention is described in detail below with reference to the accompanying drawings: [0007] Figure 1 is a perspective view of a scanning tool in accordance with the present invention; [0008] Figure 2 Is a perspective view of the scanning tool of Figure 1 employed against a workpiece.

[0009] Figure 3 Is a top view of the scanning tool of Figure 1 employed against a workpiece.

[0010] Figure 4 is a front view of an inspection system for performing nondestructive testing which incorporates the scanning tool of Figure 1.

DETAILED DESCRIPTION

[0011] The present invention detailed is for a scanning tool for non-destructive testing of engineering materials. The inspection system described comprises of the scanning tool, inspection probe and flaw detector equipment. The tool comprises of a dual axis position encoder clamping mechanism which fixes to an inspection probe to add effective dual axis scanning capability to the system. The simple and versatile design accommodates a wide range of inspection probe sizes and can operate over a relatively large variation in geometry curvature.

[0012] Referring now to Figures 1-4, the tool 100 shown in Figure 1 for performing nondestructive testing will now be described in accordance with exemplary embodiments.

[0013] The exemplary system 120 includes a dual axis position encoder clamping device 100, an ultrasonic or eddy current inspection probe 113 and a flaw detector device 118. The inspection probe and flaw detector shown in the exemplary system 120 represent any inspection probe and flaw detector device for any non-destructive testing technique including ultrasonic, eddy current, induction and hall effect.

[0014] The probe clamp assembly serves to provide mounting points for the X and Y encoding components one located at the side and the other at the end of the probe. The clamp assembly includes an adjustable fixing base rail 109 onto which clamping arms 107 and 108 are attached. On one end of the base rail 109 there is a fixed clamping arm 107 which features a slotted fixing rail on one side and a soft gripping surface 110 on the other. The second clamping arm 108 with similar features to the other has a sliding slotted connection for adjustment along the base rail and functions to open and close the clamp. The clamp adjustment is made by rotating the adjusting screw 111 which is fixed along the base rail 109 to compress the gripping surfaces 110 onto opposite sides of the probe and cause sufficient friction to securely fix it in place.

[0015] The encoding assembly consist of a rotary encoder 102 omni-directional wheel 103, spring-loaded bracket 104 and fixing plate 105. The encoding assemblies are attached to the slotted fixing rails 107 and 109 via the fixing plate 105. The slot fixing feature of the rails 107 and 109 allow each of the encoding assembly positions to be adjusted with fixing screws 112 so the planes running through the centre of the wheel thickness 116 and 117 can be aligned with the centre of the probe 113. This adjustment feature allows for a range of probe sizes to be accommodated.

[0016] The spring-loaded mechanism functions to load the omnidirectional wheel 103 against the material surface. An extension spring 106 is attached at each of its ends between the fixing plate 105 and a hinged arm 104. The arm rotates downwards and loads the omnidirectional wheel 103 against the surface 114 as the extension spring 106 contracts. The omnidirectional wheel 103 axis position is read by the encoder 102 which is mounted at the wheel end of the spring-loaded bracket where the encoders sensor is aligned with the omnidirectional wheel 103 centre axis.

[0017] The present invention is manually operated by sliding the probe 113 over the surface 114 in the chosen scan pattern whilst maintaining parallel orientation in the X plane 116 or Y plane 117. To act as a position, reference an X and Y grid pattern can be marked onto the material surface 114.

Claims

CLAIMS1. A scanning tool for non-destructive testing, comprising of: Wheel position encoding mechanisms, the first mounted to a probe clamping mechanism with a perpendicular offset to the second with their respective wheel rotation directions running along either the X or V probe scanning axis.
2. The scanning tool according to claim 1, with an encoding mechanism in which the position encoder sensor reads the rotational position of an omnidirectional wheel.
3. The scanning tool according to claim 2, where the omnidirectional wheels are magnetic
4. The scanning tool according to claim 2, with an encoding mechanism that includes a loading component which presses the encoder wheel against the inspection material surface.
S. The scanning tool according to claim 2, with an encoding mechanism that includes position encoder sensors which interface with an ultrasonic or eddy current flaw detection system and transmit positional data.
6. The scanning tool according to claim 1, with a clamping mechanism which fixes to an inspection probe using a loading component that compresses the inspection probe between gripping surfaces.
7. The scanning tool according to claim 6, where the clamping mechanism includes an adjustable fixing component for the encoding mechanism where the fixing position has the plane running through the centre of the wheel thickness aligned with the centre of the probe.